The Celtics may have home-court advantage for their second-round matchup with the Philadelphia 76ers, but Vegas and other NBA experts aren’t giving the shorthanded C’s much of a chance in the Eastern Conference Semifinals.

The Sixers are nearly three-point road favorites in Boston for Game 1 and are -390 favorites to win the series, which means Vegas believes they have about an 80 percent shot to win this series. That’s an extremely high number for a 2-3 matchup, even with the injuries involved for Boston.

The Celtics are beaten up and the Sixers are well rested after beating the Heat in five games. Philadelphia also has won 20 of their last 21 games overall dating back to March. Yet, after dissecting this matchup, the Celtics have a far better chance than most people are giving them credit for. Let’s take a closer look at the Sixers and what needs to happen for Boston to pull off the upset.

Rebounding: Cleaning up the glass is not going to be a walk in the park for Boston like it was last series against the Bucks. Not only do the Sixers have one of the best rebounding big men in the league in Joel Embiid, they also have length all over the floor. Ben Simmons is superb at crashing the glass with his size and strength, while the long arms of Dario Saric and Ersan Ilyasova create plenty of second-chance opportunities on the offensive glass. Philadelphia ranked third in the league in the regular season in offensive rebound chances and were also above-average on the defensive glass (ninth).

Brad Stevens is going to have to balance the usefulness of staying small in the frontcourt for versatility against the risk of vulnerability on the defensive glass. With Amir Johnson looming as a pest on the offensive glass off the bench as well, the C’s will have their hands full for the better part of 48 minutes in this department. Al Horford and Aron Baynes are going to need to be on point with their boxouts of Embiid, while forwards like Jayson Tatum, Semi Ojeleye and Marcus Morris are going to need to locate the length of Saric and Ilyasova early after shots to push their way out of the paint. The Sixers destroyed the Heat in the first round in this department after undersized guards constantly got matched up against Philly bigs on boxouts. If the Celtics want to win this series, they are going to have to avoid a similar fate. Greg Monroe might need to be called on for support on the glass if things get out of hand for the C’s.

Spacing: This was a weakness for the Sixers for a large chunk of the season, but that’s changed with the late season signings of Marco Belinelli and Ilyasova off the buyout market. Those additions give Philly capable 3-point shooting for seven of the nine players in their rotation, a crucial element to surround a non-shooter like Simmons. The main cause for concern for Boston will be J.J. Redick and Belinelli. Both of these shooting guards will run through off-ball screens and flares all over the court, and it’s likely one of them will be on the floor for all 48 minutes. With Jaylen Brown hobbled, it’s likely that Terry Rozier, Marcus Smart and Shane Larkin will split time chasing the duo all over the court to prevent easy looks. Boston’s bigs will be hesitant to help at times due to the shooting threats in the frontcourt. Covington, Ilyasova, Saric and Embiid are all above-average 3-point shooters when given space. This will stretch the Celtics’ defense thin and put pressure on Boston for strong rotations and closeouts.

The good news for the Celtics is that they have the defensive versatility to handle a lot of this shooting. They were the best 3-point defense in the league for a reason: their ability to handle shooters in all areas. Baynes and Monroe can be liabilities on the perimeter, which could limit their minutes if Embiid gets going from the outside, but Morris, Ojeleye, Tatum and Brown will need to ensure they get in the airspace of the Sixers frontcourt shooters. Belinelli and Redick are going to take their shots no matter what, so it will take strong communication and discipline from the C’s guards to limit separation off of screens and prevent either from getting any sort of consistent rhythm. Unlike the Bucks, the C’s won’t be able to focus on protecting the paint as much against this group.

Transition offense: The Sixers love to push the tempo with Simmons’ speed and passing ability, and now that they’ve surrounded him with more shooters, the Sixers are a lethal transition force. They ranked first in the playoffs in points scored off turnovers in the first round (21 per game), using their length and defensive pressure to create easy looks in transition. Once again, the Celtics got a nice warm up in this department against the Bucks. Whether it was off missed shots or turnovers, the Bucks punished Boston whenever they pushed the pace, and the Celtics will not be able to avoid similar lapses against the Sixers. Matching up in transition is a must, particularly with the Sixers shooters trailing the plays looking for 3-point opportunities.

WEAKNESSES

Turnovers: The Sixers turned the ball over on a higher percentage of their possessions than any other team in the league during the regular season. The biggest culprits in that department are the guys who will have the ball in their hands the most: Simmons and Embiid. The Celtics have the defenders to make life tough on both players with Ojeleye, Morris and Smart on Simmons and Horford and Baynes on Embiid. Backup point guard T.J. McConnell also has one of the worst turnover rates on the team, so ballhandling is definitely not a strength of this Sixers team. Look for the Celtics to really amp up the pressure in the halfcourt game to force players into uncomfortable spots. With Philly having a top-tier halfcourt defense, the C’s are going to be looking for easy chances in transition and forcing turnovers is the best way to make that happen.

Fouling: Only two teams sent opponents to the free-throw line more consistently than the Sixers during the regular season, making this area one of the few shortcomings of an otherwise top-5 defense. Embiid was the main culprit in this area, averaging five fouls per 36 minutes during his fourth NBA season. The Celtics will have to be careful in challenging the shot blocking of Embiid, but there is limited athleticism in the interior otherwise with this group. Saric and Ilyasova are not known for their shot blocking, and older veterans like Belinelli and Redick will struggle to keep Boston’s quicker guards in front of them (Rozier, Larkin, Brown). Philadelphia’s defense actually took a step back in the final couple months of the year as they added more offensive-minded players in Ilyasova and Belinelli. The Celtics will likely try to target both of these guys with mismatches in the post (Horford vs. Ilyasova) and with drives (wings vs. Belinelli) to try to find to get to the free-throw line.

Playoff experience: There are a few veterans that have gone deep in the postseason (Belinelli, Redick, Amir Johnson) scattered across the roster, but this is the first playoff run for the rest of this group, including head coach Brett Brown. They overwhelmed the Heat in the first round with their size and timely offensive explosions, but those luxuries will be largely gone against an undermanned but defensive-minded Celtics team. Stevens has savvy defenders to throw at Embiid and Simmons, far better players than either saw last round. How will the youngsters and Brown adjust to the wrinkles that Stevens throw at them? That uncertainty could prove to be an advantage for Boston.

REASONS FOR AN UPSET (If Jaylen Brown is healthy)

1. Terry Rozier should be a problem for Sixers: The athletic guard put on a show against Eric Bledsoe in the first round at the TD Garden, and he has the speed to create problems against an oversized Sixers lineup. Redick and Belinelli should have trouble sticking with Rozier in 1-on-1 situations, and moving a better defender onto Rozier (like Robert Covington) will create other offensive mismatches for the Celtics in a different part of the lineup (Jaylen Brown, Jayson Tatum). If the third-year guard can maintain his 3-point shooting, the Sixers will scramble trying to stop him.

2. It doesn’t get much better than Baynes and Horford as primary options to defend Embiid: The All-Star center struggled a bit in the Heat series (41 percent shooting, five turnovers per game) as he worked his way back from a broken orbital bone. The Heat had a pair of underwhelming defenders to throw at him in Hassan Whiteside (foul prone) and Kelly Olynyk (overmatched), so Embiid is in for a rude awakening with the strength of Baynes as well as Horford’s savviness. Baynes will have to work hard to avoid getting into foul trouble, but Embiid should not be able to bully either player like most other centers in this league. Boston’s ability to contain him with 1-on-1 coverage will make defending the rest of the Sixers offense a more realistic possibility.

3. The Semi Ojeleye/Marcus Smart effect: The rookie barely played against the Sixers in the regular season (21 minutes over four games) but he should be a constant presence in this series as a primary defender on Simmons and Philly’s stretch fours (Saric, Ilyasova, Covington). The switchability that Ojeleye gives Boston is the perfect answer for the kinds of lineups Brown loves to run out there (shooters with size). Smart’s ability to pester the likes of Redick and Belinelli through screens all over the floor again should keep the floodgates from opening beyond the arc.

The pick: If Brown is himself after Game 1: Celtics in 7. If not, Sixers in 7.